"We've been criticised in those areas and we think it's very important to listen to that criticism, not necessarily because it's right but because it reflects real and interesting concerns."

Stuart Prebble, the former chief executive of ITV, will lead the review. He will be tasked with investigating whether the BBC lets those know whether those holding minority reviews are blocked from taking place in phone-ins and other on-air debates.

This is not the first time the BBC has responded to criticism that it has a predominantly left-wing outlook. In 2007 a report warned that it often succumbs to liberal "groupthink", after journalist Andrew Marr had said the BBC has an "innate liberal agenda". Former media secretary Jeremy Hunt subsequently echoed that view when he claimed the BBC has an "innate liberal bias".

News of the probe will be welcomed by politicians from all political parties, after a conference season in which activists of all political persuasions expressed frustration with the way their party had been portrayed by the media.